Methods are known for affixing an elastic member or element, such as an elastomeric band or ribbon to a flexible substantially inelastic web of material defining clothing or components thereof including briefs, panty briefs, disposable diapers and the like.
Methods are known for applying an elastic element to a continuously moving web. U.S. Pat. No. 3,838,367 to Bourgois discloses a method for securing a stretched elastic element to a nonelastic fabric web and maintaining the assembled element on the web in a stretched condition until cut transversely in the direction of travel to produce separate panels. U.S. Pat. No. 4,081,301 to Buell cites other prior art patents showing ways in which an elastic ribbon is joined to a moving web of material. The Buell patent itself discloses a method and apparatus for continuously attaching discrete lengths of elastic ribbon to a moving web. The elastic ribbon is fed in a stretched condition to the web and the elastic ribbon is intermittently secured to predetermined regions of the web while so stretched. Subsequently, the web and elastic ribbon are transversely cut in an area where the elastic ribbon is not secured to the web. This step forms severed unadhered portions of elastic at both ends of each discrete length of said elastic ribbon adhered to the web. The separate unadhered ends of the elastic ribbon are allowed to relax and contract to their unstretched state.
In U.S. Pat. No. 4,337,771, Pieniak et al, there is disclosed a diaper having an elastic member disposed along both longitudinal edges. The central portion of the members are allowed to remain elastic to gather the central portion while the areas adjacent these gathered areas have been rendered inelastic to reinforce the marginal portions of the diaper. The technique for rendering the marginal areas, inelastic is to provide excess energy to the marginal areas such as with heat or ultrasonics, to render the area inelastic. Also in copending commonly assigned patent application Ser. No. 253,419, filed Apr. 13, 1981, there is disclosed a technique for incorporating stretched elastics into inelastic webs wherein heat is used to sever the elastic and render desired areas inelastic. Heat is also used to adhere the desired inelastic areas to the web.
In many of these prior art methods, in order to obtain the desired inelastic and elastic areas, adhesives must be applied in such an intermittent manner. This requires that the adhesive be precisely controlled for exact deposition. It also requires intermittently operated securing mechanisms such as adhesive applicators. Such mechanisms are very hard to operate in high speed manufacturing operations to apply intermittent, exact length glue lines. In others of these methods where the adhesive is applied continuously and heat or some outer technique is then used to render areas inelastic, the heat or other technique must be applied and must function substantially instantaneously in order to be effective. Again, an extremely difficult step to accomplish in high speed manufacturing operations. Also, when manufacturing unitized disposable diapers which have a thermoplastic film backing the application of heat becomes even more complicated because of the possible deleterious effects the heat may have on the thermoplastic film backing.